Spatiotemporal analyses of the dynamics of hypoxic tumor cells for the optimization of fractionated radiation therapy for cancers

2015 Fiscal Year Final Research Report

• Project/Area Number: 26670558
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Radiation science
• Research Institution: Kyoto University
• Principal Investigator: Harada Hiroshi 京都大学, 白眉センター, 准教授 (80362531)
• Co-Investigator(Kenkyū-buntansha): Yoshimura Michio 京都大学, 大学院医学研究科, 助教 (40597936) ; KOBAYASHI Minoru 京都大学, 大学院医学研究科, 研究員 (40644894)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: がん / 放射線治療 / 分割照射 / 腫瘍内低酸素 / HIF-1

Outline of Final Research Achievements

In the present study, we exploited a sophisticated strategy which enabled us to tag hypoxic cells with luciferase protein in tumor xenograft by using the hypoxia-responsive transcription factor-dependent Cre-loxP system, and performed spatiotemporal analyses about the dynamics of cancer cells in intratumoral hypoxic regions. What we found is that, 24 hours after hypoxic cells were tagged with luciferase protein in the regions 70-85 micrometers distant regions from tumor blood vessels, the cells were located in 85-100 micrometers from vessels. In the following day (48 hours after the tagging), the cells were detected in necrotic regions located more than 100 micrometer from vessels. These results support an idea that the interval of fractionated radiation therapy for cancer is about 24 hours.

Free Research Field

放射線腫瘍生物学